Real-World Analysis of the Clinical and Economic Impact of the 21-Gene Recurrence Score (RS) in Invasive Lobular Early-Stage Breast Carcinoma in Ireland.

Background: This study, using real-world data, assesses the impact of RS testing on treatment pathways and the associated economic consequences of such testing. This paper pertains to lobular breast cancer. Methods: A retrospective, observational study was undertaken between 2011 and 2019 on a cross-section of hormone receptor-positive (HR+), HER2-negative, lymph node-negative, early-stage breast cancer patients. All patients had ILC and had RS testing in Ireland. The patient population is representative of the national population. Patients were classified as low (RS ≤ 25) or high (RS > 25) risk. Patients aged ≤50 were stratified as low (RS 0-15), intermediate (RS 16-25), or high risk (RS > 25). Results: A total of 168 patients were included, most of whom had grade 2 (G2) tumors (n = 154, 92%). Overall, 155 patients (92.3%) had low RS (≤25), 12 (7.1%) had high RS (>25), and 1 (0.6%) had unknown RS status. In 29 (17.5%) patients aged ≤50 at diagnosis, RS was ≤15 in 16 (55%), 16-20 in 6 (21%), 21-25 in 5 (17%), >25 in 1 (3.5%), and unknown in 1 (3.5%). Post RS testing, 126 patients (78%) had a change in chemotherapy recommendation; all to hormone therapy. In total, only 35 patients (22%) received chemotherapy. RS testing achieved a 75% reduction in chemotherapy use, resulting in savings of €921,543.84 in treatment costs, and net savings of €387,283.84. Conclusions: The use of this test resulted in a 75% reduction in chemotherapy and a significant cost savings in our publicly funded health system.

Detection of novel germline mutations for breast cancer in non-BRCA1/2 families.

The identification of the breast cancer susceptibility genes BRCA1 and BRCA2 enhanced clinicians' ability to select high-risk individuals for aggressive surveillance and prevention, and led to the development of targeted therapies. However, BRCA1/2 mutations account for only 25% of familial breast cancer cases. To systematically identify rare, probably pathogenic variants in familial cases of breast cancer without BRCA1/2 mutations, we developed a list of 312 genes, and performed targeted DNA enrichment coupled to multiplex next-generation sequencing on 104 'BRCAx' patients and 101 geographically matched controls in Ireland. As expected, this strategy allowed us to identify mutations in several well-known high-susceptibility and moderate-susceptibility genes, including ATM (~ 5%), RAD50 (~ 3%), CHEK2 (~ 2%), TP53 (~ 1%), PALB2 (~ 1%), and MRE11A (~ 1%). However, we also identified novel pathogenic variants in 30 other genes, which, when taken together, potentially explain the etiology of the missing heritability in up to 35% of BRCAx patients. These included novel potential pathogenic mutations in MAP3K1, CASP8, RAD51B, ZNF217, CDKN2B-AS1, and ERBB2, including a splice site mutation, which we predict would generate a constitutively active HER2 protein. Taken together, this work extends our understanding of the genetics of familial breast cancer, and supports the need to implement hereditary multigene panel testing to more appropriately orientate clinical management.

Gene analysis techniques and susceptibility gene discovery in non-BRCA1/BRCA2 familial breast cancer.

Breast cancer is the leading cause of cancer deaths in females worldwide occurring in both hereditary and sporadic forms. Women with inherited pathogenic mutations in the BRCA1 or BRCA2 genes have up to an 85% risk of developing breast cancer in their lifetimes. These patients are candidates for risk-reduction measures such as intensive radiological screening, prophylactic surgery or chemoprevention. However, only about 20% of familial breast cancer cases are attributed to mutations in BRCA1 and BRCA2, while a further 5-10% are attributed to mutations in other rare susceptibility genes such as TP53, STK11, PTEN, ATM and CHEK2. A multitude of genome wide association studies (GWAS) have been conducted confirming low-risk common variants associated with breast cancer in excess of 90 loci, which may contribute to a further 23% of the heritability. We currently find ourselves in "the next generation", with technologies offering deep sequencing at a fraction of the cost. Starting off primarily in a research setting, multi-gene panel testing is now utilized in the clinic to sequence multiple predisposing genes simultaneously (otherwise known as multi-gene panel testing). In this review, we focus on the hereditary breast cancer discoveries, techniques and the challenges we face in this complex disease, especially in the light of the vast amount of data we now have at hand. It has been 20 years since the first breast cancer susceptibility gene has been discovered and there has been substantial progress in unraveling the genetic component of the disease. However, hereditary breast cancer remains a challenging topic subject to common debate.

Fine needle aspiration cytology in symptomatic breast lesions: still an important diagnostic modality?

The objective of this study was to make an assessment of the utility of fine needle aspiration cytology (FNAC), in a "one-stop" symptomatic breast triple assessment clinic. Controversy surrounds the optimal tissue biopsy methodology in the diagnosis of symptomatic breast cancer and the identification of benign disease. FNAC in the context of a Rapid Assessment Breast Clinic (RABC) allows the same day diagnosis and early treatment of breast cancer, with the immediate reassurance and discharge of those with benign disease. We analyzed prospective data accrued at a RABC, over a 4-year period from 2004 to 2007. All patients were triple assessed, with FNACs performed on site by two consultant cytopathologists. Investigations were reported immediately, and clinical data were captured via a database using compulsory data field entry. There were 4487 attendances at our RABC, with 1572 FNACs were performed. The positive predictive value of FNAC with a C5 cancer diagnosis was 100%, 95.6% for a C4 report, with a complete sensitivity of 94%. The full specificity of correctly identified benign lesions was 77.4%, with a false negative rate of 3.85%. This enabled 66% of patients attending the RABC to receive a same day diagnosis of benign disease and discharge. FNAC is highly accurate in the diagnosis of symptomatic breast cancer in an RABC. FNAC allows accurate diagnosis of benign disease and immediate discharge of the majority of patients. In this era, when a large majority of patients have benign disease, we believe that FNAC provides an equivalent, if not better, method of evaluation of patients in a triple assessment RABC.

Establishing a family risk assessment clinic for breast cancer.

Breast cancer is the most common cancer affecting European women and the leading cause of cancer-related death. A total of 15-20% of women who develop breast cancer have a family history and 5-10% a true genetic predisposition. The identification and screening of women at increased risk may allow early detection of breast cancer and improve prognosis. We established a family risk assessment clinic in May 2005 to assess and counsel women with a family history of breast cancer, to initiate surveillance, and to offer risk-reducing strategies for selected high-risk patients. Patients at medium or high risk of developing breast cancer according to NICE guidelines were accepted. Family history was determined by structured questionnaire and interview. Lifetime risk of developing breast cancer was calculated using Claus and Tyrer-Cuzick scoring. Risk of carrying a breast cancer-related gene mutation was calculated using the Manchester system. One thousand two hundred and forty-three patients have been referred. Ninety-two percent were at medium or high risk of developing breast cancer. Formal assessment of risk has been performed in 368 patients, 73% have a high lifetime risk of developing breast cancer, and 72% a Manchester score >or=16. BRCA1/2 mutations have been identified in 14 patients and breast cancer diagnosed in two. Our initial experience of family risk assessment has shown there to be a significant demand for this service. Identification of patients at increased risk of developing breast cancer allows us to provide individuals with accurate risk profiles, and enables patients to make informed choices regarding their follow-up and management.